Thread: Need more towing power badly

You can have the ECU chipped & some plenum mods done but there is no substitute for engine capacity.

Have you had the car checked out for any faults?
Or are you able to drive a similar car for comparism?

IMHO the problem isn't so much lack of torque but where it is developed.

The 4.0l makes maximum torque at something like 3K revs, while 100Kmh is about 2200 Revs.
Unless you anticipate hills and change back to 3rd or even second as you note then you will struggle to maintain speed.
The Thor manifold of 1999 addressed this by increasing torque lower in the band.
You have a GEMS system and gains from Piggyback chips are AFAIK pretty small.
I cannot help but think that there may be something wrong with your car eg badly carboned exhaust valves that maybe trigger knock sensors early, or a plug/lead breaking down and that it is missing on one or more cylinders which is sometimes hard to pick at speed in a V8.

My 3.9 Classic with Thor manifold, head mods and piggyback tows my 700 Kg loaded camper up hills easily. I climb Mt Ousley at Wollongong at the 80Kmh limit alternating between 3rd and unlocked 4th, and it is one of the steepest highway hills in Australia. A 38A is heavier but has a much better injection system.
A 4.6 with a Thor manifold would help a lot, but have an expert check out you engine. BTW do you have vapour injection or a "gas ring" as the gas ring will reduce mid/high end power considerably, particularly if the fitter has fitted a small one .
Regards Philip A
BTW check that the accelerator opens the throttle blade fully.

If you have an Impco model 200 mixer fitted this is like a cork in the inlet. Remove it and try it on petrol without it fitted. If it is hugely better, then get a proper gas system, either 46mm bore mixer and european (complex) converter or injection.

Hello,
I regularly tow a 800kg Boat/Trailer combination and have very little problems with Downshifts ete on the Range Rover. This is both on a 4L & 4.6L. The 4L is straight Petrol at the moment and the 4.6L is Petrol/Sequential Injection Gas. The 4.6L is marginally better when using the Gas than the 4L, but I haven't noticed any huge differences.

I would be interested to see what would happen if you were able to take the LPG Injection out of your Air Flow route and see what happens running on just petrol. I'd also be inclined to try and run some SeaFoam or similar Upper Cylinder Head Cleaner through the Intake system as well.

Get it Dynoed, that way you can see if it is making the power that it should.
And you can have a tune up as well.
I recently had mine on the dyno and picked up 6 kilowats and it is running really nice now.
Put some OEM plug leads on it i would say they are the original ones and now 12 years old.

adm333 recently found out the hard way that plugs (and maybe leads) for dual fuel engines are different to those for petrol only. I was surprised about this, but maybe it is something to look at?

Other than that, check the basics like vacuum leaks around inlet manifolds, air filter condition, maf sensor operation etc. Good luck.

My 96 4.6 dual fuel is exactly the same when towing. I've had it to a trusted Rangie expert and he said it went great, not towing.

I think its true. you need to have the revs right up. Down change before the hill and floor it. It doesn't seem to matter how its driven the fuel consumption seems about the same.

If I can get an inlet hose I might try removing the gas ring and see if that helps.

Trev

Thanks for all the good advice & tips guys.
I'll certainly be taking them all on board.
I had better just add that just recently I had the heads off and reconditioned after a head gasket blew just after I brought my Rangie.
Afterwards the compression tests were all very good for an engine which has done 187,000km. All the plugs, leads and filters were replaced. It had the full service.
My mechanic who is a family member is pretty anal with the way he works.
Every vacuum hose was checked. He discovered 2 cracked vacuum hoses and a hidden split on the underside of the main air inlet hose. I thought i wasn't too bad with tinkering with cars but couldn't believe I missed these faulty hoses.
And I also had my radiator reconditioned as well just in case.
Besides a faulty idle stepper motor which he couldn't source because they are hard to come across the car was running superb.
When I'm not towing the car is fantastic. Runs a treat.
I'm starting to think that maybe it's the way I drive.

Thanks once again guys for all the input.